Not sure where to start about redirects

Redirected website is www.tlsnx.com which when typed goes to main site of www.flightleveltiming.com

How does one go about having the www.tlsnx.com site show up in google searches when one types in just the words TLSNX?

Since it is just a domain redirect and there is/was never any web page, how do I get SEO information that relates to the term TLSNX so the .com would come up in a search result if I never actually have a webpage for it?

I also have about 6 other website addresses that are/will be redirected to the same www.flightleveltiming.com which I would be looking to do the same. I am computer stupid so please make any answers idiot proof. Thanks for any help.